During a mass campaign with a newly licensed meningococcal polysaccharide ACW135 vaccine in Burkina Faso, adverse events following immunization (AEFI) were monitored up to 4 weeks after the campaign. Eighty-six AEFI cases (5.9 cases per 100,000 vaccine doses distributed) were reported. Among 22 serious events, 4 severe local reactions were considered very likely and 4 severe allergic reactions were considered probably related to the vaccination. One fatal case in a child followed protracted seizures of undetermined cause. In a setting with no prior surveillance system, adverse events were reported at rates comparable to documented rates for meningococcal polysaccharide vaccines in other settings. The findings confirm the benefits of the vaccine in the control of meningococcal meningitis.